We conducted comparative studies on the chemical and mineralogical properties of selected pedons of Spodosols (Placorthods) and Andisols (Fulviudands and Melanudands) derived from Towada-a ash of 1000 B.P. and Chuseri ash of 5000 B.P., Spodosols and Fulviudands of the climosequence showed most remarkable differences in such chemical properties as soil acidity, fluoride and phosphate reactivity, humus accumulation and composition, and clay mineralogy, chiefly in noncrystalline aluminosilicates. Fulviudands and Melanudands, however, having a biosequential relation, showed contrasting differences mainly in the properties of soil humus. Spodosols showed remarkable accumulations of Fe and Al and also displayed the existence of placic horizon. Nevertheless, one of the two Spodosols did not meet the chemical criteria for a spodic horizon. Both Andisols and Spodosols satisfied the andic properties. In this paper we also discuss Spodosol-Andisol transition problems and propose some solutions.
© Williams & Wilkins 1988. All Rights Reserved.